Hi Guys:

I have a head scratch-er here. I bought a 1997 GMC savanna van with 5.0 engine. Van has central injection (spider). it had been sitting for two years and the fuel pump was burned out, I replaced the pump in the tank and started diving the truck, no problems. I drove the truck 1800 miles from new Orleans to las Vegas, ran perfect. after being in Vegas for a couple of weeks, the problem started( 110 degree days out here)

the truck starts cold and runs perfect for 20 to 40 minutes, but if you shut it off it will not start again. i put a gauge on the injector rail and i see that when it is hot it has low pressure (below 45psi won't open injectors). ok, so i assumed my pump could be bad even though it is new. i installed a booster pump from auto zone with separate wiring and switch to prove the problem. Truck starts fine with both pumps but then does exactly the same thing after it gets hot, won't restart until you let it cool for about a half hour or hour, then starts and runs for another 20 to 40 minutes.

I have an account with all data and i have read everything i can but this thing is crazy, i think there may be something in the electrical circuit heating up but what is it? replaced the pump relay.

ps: no codes coming up on scanner except p1351

Thanks. Equipman2

The first thing to determine when you have the re-start problem is whether it is a fuel or spark issue. The next time it won't start, determine if you are getting spark to all 8 cylinders. If not, one possibility is a crank shaft position sensor, which can act up when heat soaked. Have you scanned for DTC'*?

Hey, thanks for the quick response, the only code that i get on my scanner is p1351 which is high coil voltage,etc. in my reading of other posts ,someone said this code can come up when excessive cranking is done, not sure. would the crank sensor throw a code? by the way , the crank sensor is in the base of the distributor, correct?

Thanks

Also, when i spray carb cleaner in the intake hose , it will run for a few seconds to burn up the cleaner, i thought this meant it was fuel

When it wont start, make sure you have spark.

Another thought, your engine temp sensor. If it'* reading over heated, it wont start.

Ok, thanks for the input, i am going out to run it now and see if it has spark when hot, makes sense what you say, if the crank sensor talks to the computer and is not reading , then it will not power up the pump to run.

Thanks again

Equipman2

The CPS is behind the crank pulley. It will not throw codes.

these engines have the single coil on the intake, the coil sounds like its going high resistance when hot. i would try starting the engine then put a heat gun (carefully dont melt anything) on the coil see if it quits, that would be my guess